Automatic telephone system



R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Oct.. 9 1923. 1,469,807

' A lavez-ZID? EUC/Pneu lcit. 9 1923.

R. G. RICHARDSON -AuoMATIc TELEPHONE `SYSTEM 3 Sheets-Sl-wot 2 FiledAJan. 8 191'? tuant-:P

R. G. RICHARDSON' AUTOMATIC TELEPHONE SYSTEM 1917 3 Sheetsv-Shblat 3Filed Jan. 8

m mmm mm m, m En, m N l BODNEY UTMATIC TELEPHONE SYST elle.

lneon, or cmcnco, unimore, assrenoa 'ro auroarrc nnnlcrarc Y, orcnrcnec, rumors, a coarona'rrcn or rLLors.

application ale'd January E, 1917'. Serial No. 141,130.

To all 'whom zt may concer/h.'

Be it known that l RODNEY G. RICHARD- soN, a citizen of the nited Statesof America, and a resident of Chicago, county of Cook, and State ofillinois, have invented certain new and useful Improvements in AutomaticTelephone Systems, of which the following is a specification.

My invention relates in general to automatic telephone systems of theusual percentage type in which automatic switching apparatus is providedat the exchange, through the medium of which calling subscribers areenabled to obtain desired connections; and embodies a number of featureswhich will be pointed out and described hereinafter.

One of lthe principal features of my invention relates to an lmprovedtrunking system whereby subscribers are enabled to call an operator forthe purpose of placing a long distance call, or for other purposes.

In' a well known type of automatic system employing individual lineswitches, first selector, second selector, and connector switches, ithas been customary in the past to assim a certain level, for example,the tenth level, of the rst selectors to the trunks extending torecording toll operators. With this arrangement when a subscriberdesires to place a long distance call he will remove his receiver andthen proceed to manipulate his calling device in accordance with thedigit 0, thereby operating a -first selector to extend vconnection to arecording operator. While this method of operation is fairly simple forthe subscriber,

it has the great disadvantage of reducing the capacity ofthe exchange by1000 lines, which is often such a serious objection as to warrantextraordinary edortsto overcome In myv improved trunkin system, thegroups of trunk lines exten ing from'the individual line switches to theirst selectors r are combined into main groups of line terminating in anidle first selector. If

a connection to another subscriber is desired, the calling subscriberthen operates his calling device as usual to obtainthe lconnection andit is to be noted here 'that all thelevels of the .first selector are'assigned to main groups of subscribers lines, none of them v beingreserved for the toll recording trunks'.

Suppose, however, that the calling subscriber esires to obtainconnection with a toll recording operator. In this case he has simply topress a button with which his substation instrument is lprovided as aresult of which operation any idle fin er switch is set in motion-tofind the trunk line to which the calling subscribers line is connectedand extend it to an operators position.

Another' important feature of my invention relates to the finderswitches and has for its object thesecuring rapidity in extendingconnections. lt has been mentioned before that each main'group ci trunklines which is accessible to a given group of linders isvmade up of anumber of smaller or sub-groups. The finder switches employed arepreferably of the type which have primary movement to select groups(sub-groups in this case and secondary movement to select the individualtrunk line vin the group.` By my invention, however,

the finder switches have no normal position as regards the groups andwhen disconneccuit is provided whereby a calling sub-- scriber willstart the finder switch which at the time happens to be'associated withthe group of lines ot which his line is one, thereby permitting theprimary movement of the switch to be eliminated; or in case there is atthat time no finder switch associated with his group, that finder willbe started which is at the time associated with the of extreme v nextgroup in reverse order, etc. ln other words when a calling subscriberresses his button to call an operator, he wil start that finder switchwhich requires the least movement to locate the group; and if there isalready a finder associated with that group,

that finder will be used, and no primary or group selecting movementthereof is required.

05 I. tending to the selector switch E. The selec- 'llhe foregoing/andother useful objects net now specifically mentioned are attained ment H,in a system embodying the -principles of my invention. The connectionhasv been established through the mediumjof the individual line switch C(Fie. 1) and the finder switch (Fig. 2). In F ig. 3 I have shown thestarting circuit extending through three finder switches of the samegroup;

while Figs. 4 and 5 are views4 of a special bank with which each finderswitch is provided.

` The substation A (Fig. 1)l may be of any approved automatic type,such` for example, as the substation shown in British patent to Martin,No. 1419 of 1910. As represented herein, it comprises essentially thereceiver 2, transmitter 3, switch hook 4, ringer 5, and condenser 6. Theresistance 10, in series with one of the line conductors, is normallyshort-circuited by the springs of the push but-ton 11. Being anautomatic substation, there is also provided a. pair of impulse springs7 and 8 controlled by an impulse wheel 9 through the medium'l of afinger hole dial (not shown).

The line conductors 12 and 13 of the substation A are connected at theexchange tov the individual line switch C which is of the eneral type ofline switch disclosed in the ritish patent to James, No. 26,301 of 1906;being, however, of the particular type shown in U. S. Letters Patent No.1,078,690, granted Jan. 17, 1912, to Frank Newforth. Through the mediumof line switch C the line-of' substation A when calling is given accessto a plurality of trunk lines extending to selector switches.

rlhe line switch C and a plurality of similar line switchesv arecontrolled in their trunk selecting operations by means of a masterswitch. D. rlhe master switch D is of the general type of master switchdisclosed in the above mentioned British patent to J ames, No. 26.301of' 1906; being, however, more nearly of the particular type disclosedin the British patent to Martin, No. 1419 of 1910, also previouslyreferred to. Asis well known, the function of the mas-l ter switch is tomaintain the plungers of all idle line switches which it controls inposition before the terminals of an idle trunk line.

One of the trunk lines to which the line switch 'C has access is shownin Fig. 1 exacceso? is'to be extended to an operators position,

as will be explained fully hereinafter. e

The finder switch F. (Fig. 2) is in general imilar in construct-ion tothe switch shown in'U. S. Letters Patent No. 815,176, granted March 13,1906, to Keith.,- Erickson, and Erickson, except that the side switchand private magnet are omitted, and the circuits are changed radicallyin order to permit the switch to erform the functions of a finderswitch. t is thought leestv to de.-` fer the description of the circuitsuntil later, when the operation of the complete system will beconsidered in detail.

There are, however, `a number of important differences in'mechan calconstruction which it is considered advi able to explain briefly at thistime. The Ix ith and Erickson switch above mentionedhas a bank of 100sets of contacts, each set comprising two line contacts and one privatecontact, ar-

ranged in ten groups or levels. The switchv with a private or testwiper, which is the wiper 121. The finder switch bank also has 100 setsof contacts divided into ten levels (one set in each of the three lowerlevels being shown in the drawing) and the wipers 121,122, and 123 havea vertical group selecting movement under control of the vertical Themagnet 114, and a rotary movement under A control of the rotary magnet115. So far the finder switch F is substantially like the switch shownin the Keith and Erickson patent. An essential difference appears,however, in the release mechanism.

ll provide separate holding pawls for the switch shaft for controllingits restoration in a rotary direction vand in a vertical direction.These pawls are normally in engagement with the ratchet teethof theshaft and may be of any well known construction. When the rotary releasemagnet 117 is energized the rotary holding pawl iswithdrawn to permitthe release of the shaft as regards its rotary movement and when thevertical release magnet 116 is energized the vertical holding'pawl iswithdrawn Vto permit the release. of the switch shaft vertiare permittedto close on the first rot-ary step, and the vertical off-normal springs119 and 120, which are controlled by the shaft cams 131 and 132 and thedo 133. When the shaft is in its lowest positlon the spring 119 isdisengaged from spring 120 by the cam 131. When the shaft is stepped upin the operation of the switch, the spring 119 is held in the positionshown in Fig. 2 by the dog 133 until the shaft arrives opposite thetenth level, whereupon the cam 132 disengages the dog 133 and permitsthe springs to close. v

-In addition to the foregoing details, -each finder switch is alsoprovided with a vertical strip of ten group test contacts and a verticalstrip of ten starting circuit contact sets. These test and startingcircuit contacts are preferably combined in a single bank as shown inFigs. 4 and 5, andmay be mounted in any suitable manner on the switchframe. The vertical test wiper 124 is alwaysl in engagement with someone of the vertical test contacts 134, 135, etc.; and is attached to themember 2,02 which in turn is rotatably mounted on an upward extension ofthe switch shaft 200, and is held in position by the adjustable collar203. When the switch is idle the starting wiper or contact member 125 islikewise in engagementy with some one of the contact springs 129, 126,etc., of the starting circuit contact sets. When the finder switch isengaged in a connection, however, the starting wiper 125 is disengagedby means of the magnet 113. The magnet 113 is rigidly mounted on theswitch shaft which forms its core, and is provided with a U shapedarmature 204 which is rotatable to a limited extent on the shaft. Theupper leg 208 of the armature 204 is preferably of brass to avoidshort-circuiting of the magnetic circuit. vWith no current flowing inthe Winding of magnet 113. the armature 204 is held by the spring 206 insuch position that the wiper 125 engages the contact spring 129 (or'corresponding spring in another level), and the spring 206 hassufficient tension to cause the-spring 129 to be separated from itsresting contact. lVhen the magnet 113 is energized, the armature 204 isrotated several degrees and the starting wiper 125 is thereby disengagedfrom the contact spring of the starting circuit contact set oppositewhich it is standing and the springs of such set are permitted to close.

With each of the ten sub-groups of trunk vwinding 142 of the rela linesto .which .the finder switch F has access there is associated a set ofthree group relays which among other things contr'ol the removal of thetest 'potential from-the finder switch group test contacts. Thus,referring to Fig. 1, the first group of trunk lines, not shown in thedrawin but which are understood to b e multipfed in the iirst levels ofthe group of finder switches of which the finder switch F is one, areprovided with the group relays 136, 137, and l138; lwhile the secondgroup of trunk lines, which is'similarly multipled in the second levelof the finder switches, and which includes 4the trunk line terminatingin'the selector E, is provided with the group relays 139,l 140,'and 141.It is understood that each of the other elght groups of trunk lines towhich the group of finder switches has access is similarly provided witha set of group relays. The relay 136, when energized, removes groundpotential from the group test contact 134 and its multiples in the banksof the other finder switches of the group, and

the corresponding relays in the other sets' of group relays perform likefunctions.

Vith each set of group relays there is associated a starting wire.Considering the second ciated set of group relays, the starting Wire 244is multipled at one end to all the first selectors in which thetrunklines terminate, including the selector E; it includes the 139; andit termi-- nates in spring 126 o the second set of. starting circuitcontacts of the finder switch F, which it should be mentioned is'assumedto be the first finder switch' of the group. In the same way each of theother groups of trunk lines has a starting wire' which extends by Way ofthe associated group relay corresponding to relay 139 to the startingcircuit contact bank in the lirst finder switch; and since there are.ten groups of trunk lines there will be ten of these starting Wires. Thestarting Wires are not multipled in the other finder switches of thegroup directly, as are the vertical and rotary test contacts and theline contacts, but are tapped onto a continuous series or loop circuiteX- tending thro-ugh all the finders and which can be best understood byreference to Fig. 3.

In Fig. 3 there is shown the wiring of the starting circuit cont-actbanks of three finder switches, this number being thofught suiiicientfor purposes of illustration. Beginning with t-he starting Wire 044which is associated with the tenth group of trunk lines, the circuit maybe traced by way of the top or tenth sets of starting circuit contactsprings group of trunk lines and the asso? of the three finder switchesin series and conductor 300 to the starting wire 944 of the ninth group,thence by way of the ninth sets the finder switch F. Briefly stated, thestarting wiper of each idle finder switch opens the starting loop and isin electrical connection with the upwardly extending portion thereof.

In addition to the tenf sets of group relays, there is provided a pairof relays 150 and 151, which are 4common to these up relays, or in otherwords, which are in ividf ual to the group of finder switcheswhichincludes the finder switch F. The relay 150 is a general alarmrelay, while rela-y 151 controls the ground connection to the commonconductor 152. This latter conductor, it may be mentioned, is multipledto the irst selectors of all the ten groups'of t-runk lines which areserved by the finder switch F andA associated finders. p

The operators equipment, which has been indicated in Fig. 2 by thereference character H, comprises -a group of relays, the signal lamps Land L and a key K. The utility and o eration of this apparatus will bedescribed ater.

1 have shown throughout the drawings a plurality of batteries, lbut itis to be understood that in accordance with the usual prac tice theremay be and is preferably but one battery, the positive pole of which isgrounded.

Having described more or less briefly the apparatus involved, l will nowproceed to explain the operation of my improved telephone system. Inorder to afford an opportunity of describing the operation of theselector E, it will first be assumed that the subscriber at substation Adesires to obtain connection with another subscriber, after which theassumption will be made that the same subscriber desires to communicatewith the operator Ipresiding over the operators equipment this latterbeing the complete circuit connection shown in thedrawings andpreviously referred to.

Referring to Fig. 1, when the subscriber at substation A removes his'receiver to initiate the call, an energizing circuit is completed overthe line conductors 12 and 13 for the line relay 16 of the line switchC.

Upon attracting its armature,- the line relay the bank springs 30-33,inclusive, into en-V gagement, respectively, with contacts 34-37,

inaeaeor inclusive; and the latter disconnecting the line conductors 124and 13, respectively from ground and from the line relay 16. y theengagement of bank 4springs 80 and '33', respectively, with contacts 34and 37, the line conductors 12 and 13 are extended, respec-v tively, tothe low resistance relay and the l1ne relay 50 of the selector E, itbeing noted that the conductor 12 passes also through the lower' windingof the line relay 50.

The relays and 40 are accordingly energized 'over the loop circuitincluding substation A and the line relay 50, upon attracting itsarma-ture, closes a circuit for the slow-acting release relay 51. Uponenergizing in turn, the relay 51 completes a holding circuit for theline switch C which may be traced as follows: und at GT, contact 63',armature 64, con uctor' 38, contact 35, bank spring 31, and holdingwindlng 18`to battery Since the line relay 16 is slow acting, it retainsits armature to maintain the pull-in winding 17 energized until afterthe above holding circuit has been established. A branch of the holdingcircuit extends .by way of conductor 19 to multiple test contacts in thebanks of connector switches having access to the line of substation A,where by a ground poten-tial on these test contacts the said line ismade busy. By the engagement of bank spring 32 with contact 36 themaster switch D is operated in well known ina-nner to advance theplungers of all the remaining idle line switches into position beforethe terminal of the next idle trunk line.

rllhe foregoing operations have occurred in response to, the removal ofthe receiver at substation A. It has been assumedthat the callingsubscriber desires to connect with another subscriber in the exchangeand he will therefore lproceed to operate his calling device inaccordance with the irst digit in the desired number. By the operationof the calling device, a series of interruptions is produced in the linecircuit which as just explained now includes the line relay 50 and therelay 40 of the selector E in series. At each interruption of itscircuit, the line relay 50 deenergizes momentarily and ksends an impulsefrom ground G6 throu h the slow acting relay 52 and the vertica -magnet53 in series. Responsive to these impulses the vertical magnet operatesto raise the switch shaft step by step until the wipers 70, 71, and 72arrive at that horizontal level of' bank contacts in which are locatedtrunk lines extending to the desired main group of subscribers lines. yAt the first interruption of the line circuit the relay 40 deenergizesalso and by closing the back contact of armature 41 short circuits itswinding so that it is excluded from the line circuit` during subsequentimpulses. Since the llll vto prevent the closure o relay 40 does notagain energize after the first interruption of the line circuit, theoff-normal contact springs 44 are provided the finder switch startingcircuit. The off-normal springs 44 are permitted to 'separate on thefirst upward movement of the switch shaft,v The slow lacting relay 52,which as pre1 viously'mentioned is included in the vertical magnetcircuit, .is energized at lthe first impulse and retains its armatureattracted vduring the vertical movement of the switch. Upon the firstupward movement of the switch shaft the off-normal springs 58 areclosed, thereby completing an initial energizing circuit for relay 55which may be traced as follows: ground at G7, the Working contacts ofamature 64, the armature of relay 52 and its working contact, the saidoff-normal springs 58, and the winding of relay 55 to battery Ba.- Uponenergizing, rel-ay 55 prepares at its lower armature a circuit for therotary magnet 54, which is held open during the vertical movement of theswitch by the relay 52, and at its up per. armature locks itselfindependent of the relay 52 by closingl the following circuit:

rounded conductor 38, lower armature of t e rotary magnet 54 and itsresting contact, upper armature of -relfay 55 and its working contact,junction point 80, off-normal springs 58, and the winding of relay 55 tobattery B".` At this point it'should be mentioned that bv the closure ofthe off-normal springs 58 the line switching relay 63 was connected inseries with relay 55. But since the junction point 80 has already beenconnected to ground as just described, it will be seen that theswitching relay 63 is short `circuite for the present and remainstemporarily inoperative.

lVhen the slow acting relay 52 deenergizes at the end of the series ofimpulses it completes at its back Contact Vthe previously mentionedcircuit of the rotary magnet 54, extending from ground G7, ovei` anobvious path. Upon energizing, the rotary magnet operates to rotate theWipers 7 0, 71, and 72 into engagement withjthe first set .of bank'contacts of the horizontal `level opposite which they were raised. Neartheend of its stroke the rotary magnet also breaks. at its lowerarmature, the locking circuit of relay 55; and at its upper armature thevcircuit-connecting the line switching relay63 with the junction point80. Upon deenergizing, the relay`55 breaks the energizing circuit of therotary magnet which accordingly retracts its armatures to again closethe contacts controlled thereby. The operation now depends on whetherthe first trunk line, the terminals of which are now engaged' by theselector wipers. is busy or not. Assuming that this trunk line is busy,the test contact upon which the test or private wiper 71 is resting willhave ground potential vuponv iti-which .ground potential will serve tomaintain the switching relay 63 short-circuited and also to againenergize the relay v55. The rotarv magnet circuit is therefore againclosed. and the same operation is repeated. A It willbe seen then thatthe relay 55 will operate as an impulse sender to step the switch wipersaround through the medium of thel rotary magnet as long as the testwiper 71 continues to engage busy or grounded test contacts. When anon-bus provide against the deenergization of rela s 50 and 51; shiftsthe private wiper to t e grounded terminal of switching relay 63; anddisconnects the line conductors from the line relay,50 and extends themby way of theline wipers and 72, and the line conductors of the selectedtrunk to the line relay of the second numerical switch of the series,which may be a second selector switch similar to thel selector E. Theline relay of the second selector is accordingly energized over the linecircuit and through the medium of the usual slow acting release relayconnects ground to the third conductor of the selected trunk` therebyestablishing a new holding circuit for the line switch C and theswitching relay 63 which includes the private wiper 71 andthe upperarmature of relay 63 and its working contact. It is understood, ofcourse, this new holding circuit is completed' before the slow actingrelease relay 51 has had time to deenergize.

Having operated the first selector E in the manner above explained, thecalling subscriber may now manipulate the dial of his calling device inaccordance with the remaining digits in the number, whereby the secondselector and the final connector switch are lcontrolled in the usual andwell known manner to extend the connection to the desiredsubscribers'line. The foregoing operations,

together with the signalling of the called sub-- scriber and the finaldisconnection of the switches after conversation are the usual onesstation A in extending a connection to an operator. Since thepreliminary operations responsive to the removal of the receiver orungrounded contact is reached and t e rotary magnet are the same, itwill be assumed that the subscriber has removed his receiver, that the50, 40, and 5'1 ofthe selector are inenergized'v lineswitch C hasoperated .to extendconnection to the selector E, and that the relays`relay 50 is not'v aected by vthe decreased current flow in the linecircuit and maintains its armatures attracted. `Relay '40, however, ismar inal and at once retracts its armature, there y short-circuitlngltself at the back contact of armature 41 so that it` will not again beenergized when the push button at the calling substation is released. Asa further result of the deenergization of relay a-starting circuit forinitiating the operation of fan idle finder switch is closed over thefollowing path: ground at G2, resting contact of armature 153 and thesaid armature, common conductor 152, off-nor-f mal s rings 44 of theselector E (now closed amature 43 and its working-contact, armature 42and its resting contact, windin 84 of relay 82, armature 87 and itsrestl contact, starting wire 244 including the w1nding 142 of relay 139,the Second set of starting, circuit contact springs 126 and 127 offinder switch F, conductor 128 including in series the second set ofstarting circuit contact springs in' each of the other finders of thegroup (it being assumed that no finderhas its wipers standing oppositethe second level, see Big. 3), starting circuit oontact spring 129 ofthe first set, starting Wiper 125 of finder switch F now inengagementtherewith (it being assumedv that the wipers of finder switchF are standing opposite the irst level), and the winding 101 of thestarting relay 100 to battery B1".

A lt will be noticed that there are two branches connected to the abovecircuit at points between the spring 129r and the starting relay of thefinder switch. One branch extends from the starting wire 244 through thewinding of relay 141 to battery B, while the other branch extends fromstarting wire 144 through the winding of relay 138 to battery' B". inorder to secure the proper operation ofthe various relays associatedwith the starting circuit, they are wound to approximately the followingresistances: winding 84 of relay 82, 100 ohms winding 142 of relay 139,400 ohms; winding 101 of relay 100, 400 ohms; and, relays 138 and 141,-v

' 10,000' ohms each.- To proceed with the operation, upon the closure ofthe starting circult, the relays 82, 138,` and 141 are not suicientlyenergized to enable them to attract their armatures; the former relaybeing. in series with the higher resistance relay 139 andthe addedresistance of the .neeaeor multiple branches be ond, andthe two latterrelays being shunte by the comparatively low wound relay 100 ofthelfinder switch,

than relay 100. Considering rst the func'-l tions of relay 139, thisrelay, upon attracting its armature 1'55, disconnects ground G3 from thegroup test contact 135 and its multiples -in. the -nder switch banks andsubstitutes therefor the winding of relay `140. Upon attracting its.lower armature 154, relay 139 vcloses a locking circuit for itself overthe following path: ground at G5, coon rela armature 156 an the saidarmature, winding 143 of relay 139, and the working con- 151; restingcontact of tact of armature 154 and the said armature v to battery B".By the energization of the coon relay 151, ground G2 is discon nectedfrom the conductor 152 to prevent for the moment the starting of anyother finder switch. l Simultaneous with the closure of the abovelocking circuit for relay 139, and before relay 151 has had time toattractits armature, the battery B5 is connected direct to the startingwire 244, thereby causing a momentary increased current impulse to flowthrough winding 84 of relay 82. Upon energizing relay 82 first closes alocking circuit for itself4 as follows: grounded-conductor 38contact 91,spring 92, working contact of armature86 and the said armature, and thewinding 83 of relay 82 to battery B4. Further results of theenergization of relay 82 are the opening of the circuit of verticalmagnet 53 aft armature 85, the opening of the starting circuit atlarmature 87, andthe removal of ground `G4 from the, test contact 163and its multiples in the finder -switch banks.

Returning now to the starting relay 100 of the finder switch l", thisrelay is sufliciently energized beforel its winding 101 isshort-circuited by the application of battery B5 to the starting wire atrelay 139, to close a locking circuit including its other winding whichmay be traced as follows: ground at G1", armature 1.71 and its restingcontact, armature 166 and its working contact, vwinding 102 of relay100, and the windingr 104 of the Vertical test relay 103 to battery B11.'Relay 100 is thus maintained energizcd temporarilyindependent of thestart ing circuit and at the same time relay 103 is operated. Uponenergizing, relay 103 closes the following circuit: ground at G12,working contact of armature 170 and the said armature, winding of slowacting relay 106, and the winding 109 of the rotary test relay 107 tobattery B1?. Upon energizing, relay 106 closes a locking circuitl forthe ISOA vertical test relay 103 as follows: ground at G9 (Fig. 1),upper armature of relay 136, group test contact 134, test wiper 124,working contact of armature 172 and the said armature, armature 169 andits working contact, and the winding 105 of relay 103 to battery B11.Another circuit closed by: relay 106 extends as follows: ground at G10,armature 171 and its working contact, and the windingof magnet 113 to'battery B13.- Upon energizing, the magnet 113 disengagcs the startingWiper 125'from spring 129 and thereby permits the ,starting loop to be'closed past the iinder switch\l`. A

branch-of the circuit'of magnet 113 may be traced from junction point176 by way the armaturel of relay 100. Relay 100 is therefore permittedto deenergize, but-relay 103 remains energized by reason of the circuitthrough its lower winding 105. A circuit for the vertical magnet 114 maynow be traced as follows: ground at G11, armature 168 and its workingcontact, armature 167 and its Aresting contact, armature 177 and itsresting contact, winding of vertical magnet 114, and the armature 178and its rest-- ing contact to battery Bl. Responsive to the closure ofthe above circuit the vertical magnet 114 is operated to step. up thelinder switch shaft one ste thereby raising the wipers 1214125, incusive, to the second level. The vertical magnet interrupts its ow'ncircuit near the end of its stroke and therefore immediately retractsits armature, but before its circuit can again be closed, the verticaltest relay has deenergized due to the test wiper 124 leaving thegrounded -test contact 134 and engaging the nongrounded test contact135. It will be understood of course that if the trunk line whichthefinder switch is in search of were located in one of its upper levelsthe vertical mag net would be energized intermittently toraise theswitch shaft step by step until the test wiper 124 arrived at the rightlevel.

Proceeding with therexplanation, the first l result of thedeenergization of the test relay 103 which should be considered is theclosure of a circuit for group relay 140 (Fig. 1) as follows: ground atG11, resting conv tact of armature 169 and the said armature, armature172 and its working contact, test wiper 124, test contact 135 armature155 and its working contact, and the winding of relay 140 to battery B8.Upon attracting its armature 156, relay 140 breaks the locking circuitof relay 139 which includes also the common relay 151. Upondeenergizing, re-

lay`139again connects ground Gr'3 tothe second level of grouptest'contacts in the finder banks; while the relay 151, upondeenergizing, again connects -ground G2 tov thc common conductor-152. Asecond calling line 1s now able to startanother finder switch, eventhough the finder switch'F has not yet'locate'd the trunk line. to whichthe.

first calling line is connected. 'f

Returning to the -relay103 (Fig. 2),'addi- 'tional results of itsdeenerg'ization are the breaking-of the circuit of slow actingv relay106, relay107 remaining energized by reason of its previously describedlocking circuit; and the closure of a'circliit for the rotary magnet 115which. mayI be tracedas follows: ground at G, armature 168 and l itsresting contact, winding of slow acting relay 110, armature 175 and itsworking contact, winding of the rotary magnet 115, and

the lower armature thereof to battery B15.

vUpon the closure of the above circuit lthe slow acting relay andthejrotary magnet are energized in series; the former connectingl groundGr14 tothe circuit ofmagnet 113 to provide against the deencrgization of.relay 106,. which occurs an instant later; and the lat-ter rotating theswitch shaft to brlng the Wipers 121, 122, and 123 into engagement withthe `tirst set of contacts of vthe second level. Nearthe end of itsstroke l the rotary magnet interrupts its own circuit .and also, at itsupper armature, the previously described locking circuit of testrelay107. lBy. the latter operationr the continued energlzation of the testrelay 107 is made contingent on the presence of ground potential uponthe test contact with which the test wiper 121 is now in engagement.Assuming that the set of cont-acts which the finder is in Search of isnot the first set in the second level, current will -flow from ground onthe test contact'by way of test v wiper-121, the lower working contactof armature 174, the said armature and its upper working contact, .andthe'winding 108 of relay 107 to battery B12. Since the rotary magnetopened its own circuit at the same time that it opened the initiallocking circuit of the test relay it will deenergize immediately andagain close both circuits, when the same operation will be repeated .andthe wipers will be advanced to the second set of contacts of the secondlevel. Thus it will be seen that the test relay 107 willcontinue to beenergized and the rotary magnet 115 will continue tostep the shaftaround as long as the test wiper 121 engages grounded test contacts. Assoon however as the wipers arrive at the contact set associated with thetrunk being hunted for, which is the contact set leaflet-165, the test'wiper 121 will find no ground potential on the engaged testcontact,vwhicl1 is the test contact 163,I and the test relay 107 willtherefore deenergize as soon as its .locking circuit is opened by therotar magnet, and will break the circuit of `the Thus the Wipers of thefinder are brought tol rest in engagement with the contacts of the trunkline to whichv the line of substa;

tion A is connected. c c

The instant the test relay 107 -deenergizes the rollovvin lcircuit iscompleted for the switching ne ay '111: ground at G14, 'armature 173 andits working contact, junction point 176,' upper armature of the `rotarymagnet 115 and its resting contact, armature 1711 and its restingcontact, and the windin ot switching relay 111 to battery B1". ponenergizing, the switching relay at its armatures 194; and '195. connectsthe line wipers 122 and 123, respectively, with the trunk Jconductors191 and 192; breaks v atA its armature 18a a contact in the circuit ofthe release magnet 117 Vin order to guard against the deenergization ofthe slow-acting relay 110; and finally at its armature 185, completes acircuit for relay 89 of the selector E which may be traced as a branchof the circuit of relay 111 as follows: junction point 193, workingcontact of armature 185 and the said armature, junction point 180, testwiper 121, test contact 163, conductor 160, armature 88 and its workingcontact, and the winding of relay 89 to battery B17. Upon attracting itsarmature, relay 89 substitutes ground Gs for ground G in the lockingcircuitof relay 82. The

abovecircuit of relay 89 also serves to supline relay 181 is energizedinmultiple lwith the line relay 50 of the selectorE, and upon attractingits armature completes-xa circuit for the slow actingl relayf182 as.follows:v

ground at G1", armat'-l`1re" 186 and'itsworking contact, winding ofrelay j. 182,V armature 189 and its resting contact,'and the uppercontacts of key K to battery B18. Upon energizing, relay 182 completesthe followin holding circuit as a substitute for ground n; groundat G17,working contact of armature 187 and the said armature, and the conductor190 to junction point 180, where vthe -circuit divides, one branch eX-tending over a vpreviously described path t-o` relay 89 of the selectorE, and the other atter to prevent its reenergization.

Maase? branch extending by way of armature 185 and its working contactto junction lpoint 193, lwhere the circuit again divides into branchesextendin to relay 111 and to mag- 1 l.'

how the call-signal lamp L is illuminated.y As soon as the relays 106.and 107 are y energized followingethe closure of the starting circuit,a circuit through lamp L may i l time to deenergize after the lastrotary iml be traced as follows: ground at G1", arma\ kS0 ture 171 andits 4working contact, junction point 176, upper armature of the rotary.

conductor 190, armature'188 and'its resting contact, and the lamp L 'tobattery. B18.

It will be seen then that the call signal lamp is lighted immediatelyupon the start- .ing `oi? the nder switch, thus giving the operatorwarning in advance of the'completion ofthe connection that suchconnection is to" be established.v After the finder has operated,current is of course supplied to lamp L from ground G17,

The operator will respond to the si nal thus received by operating thekey l to the position shown in the drawing, thereby bridging her headset (not shown) across the trunk conductors 191 and 192, and at the`same time removing the short circuit from relay 183. Relay 183 -isaccordingly energized in series with relay 182, and u on attracting itsarmatures 1881and 189, shifts the conductor 190 from lamp L to lamp L',and also opens a contact in its shunt circuit so that if the key K isrestored it will not.

again be short-circuited. The operator may now converse with the callingsubscriber and ascertain his wants as is usual in such cases. 1f itshould become necessary for the operato-r to have the subscriber waitWhile certain facts, his credit for example, are beinginvestigated, shemay restore her key to normal osition. When this is done the lamp L (ared lamp, preferably) is forget the cally.

will break the circuits of slow-acting relays- 51 and 182. When therelay 51 deenergizes, the holding `circuit including the vWinding' iatlighted to insure that the operator will not ,switch,

finder switch will be deenergized. Relay 89,

' thereby cutting the 18 of line switch C will be broken and the lineswitch will be released in -the usual manner. Upon the deenergization ofrelay 182, the relay 89 of selector E, the relay 111 of the finder andthe magnet 113 of the upon 'retracting its armature, breaks the lockingcircuit of relay 82 thus permitting that rela to restore and againconnect ground 1 to conductor 160. When the relay 111 retracts itsarmatures, a circuit is closed for the rotary release magnet 117 asfollows: ground at G14, armature 173 and its resting contact, restingcontact of armature 184 and the said armature, winding of' releasemagnet 117, and the rotary oli'- normal springs 118 to battery B1. Uponenergizing, the release magnet 117 withdraws the rotary holding pawlfrom the shaft, thereby permitting the restoration of the shaft andwipers in so far as their rotary movement is concerned, and as soon asthe return is effected the circuit of the release magnet is again openedat the Aoff-normal springs 118.

The magnet 113 being now deenergized, as soon as the shaft is releasedthe starting wiper 125 will engage the starting circuit contact spring126 and will separate it from spring 127, finder switch in on thestarting loop again. After disconnection,

therefore, the finder switch wipers are left standing opposite the banklevel last served; or in other words, the wipers ordinarily are notreleased as regards their group selecting movement.

, Under certain circumstances, however, for example as when the wipersare standing opposite the tenth level and it 1s necessary to cause themto hunt over a lower level, the finder switch shaft is restoredvertically by energizing the vertical release magnet 1 16, but suchrelease is always eiected durlng the establishment of the connection andnot upon disconnection. In order to explain the vertical release it willbe assumed that when the calling subscriber at substation A pressed hisbutton to call the operator the finder switch F was standing oppositethe ninth level instead of the first level. Now when the starting wire244 is grounded the finder switch F' will be started as before (therebeing no other finders cut in on the starting loop between the secondand ninth levels) and the vertical magnet 114 will be operated to raisethe wipers to the tenth level. Since the group test contact for thetenth level is grounded the test relay 103 will not deenergize. As thearmature of the vertical magnet reaches nearly the end of its strokeandjust as the magnetcircuit is interrupted, the cam 132 on the shaftengages the dog 133 and releases the olf-normal spring 1.19, whichthereupon makes contact with sprlng 120 and closes thefollowing circuit:ground at G, armature 168 and its working contact, armature 167 and itsrestmg contact, winding of relay 112, and the off-normal springs 120 and119 to battery B20. Upon energizing, relay 112 breaks the -tion of thevertical magnet 114 is of `course suspended, and also the test relay 103is locked as previously mentioned to prevent its deenergization when thetest wiper 124 passes the test contact 135 on the way down. With thecomplete return of the shaft, the earn 131 has separated the olf-normalsprings agaln, whereupon the release magnet circuit 1s :broken and thecircuit of the vertical magnet 114 is again closed. Thereupon the finderswitch resumes its operation and the calling line is found as before.

T he purpose of the relays 138 and 141 and slmllar relays (not shown)associated with the other eight suboups will now be briefly explained.Tese relays are provldcd for the purpose of giving an alarm 1n case thefinder switches are all busy when a call isjattempted to be made, or incase there is an open circuit somewhere in the starting loop. In theformer case all ten of these relays will be connected to whicheverstartlng wire is grounded and since they are not shunted' by thestarting relay of a finder switch, will be energized in multiple tolight their associated lamps in series with the alarm relay 150. Relay139 is so adjusted that it will not operatively energize in serieswith'1000 ohms. In the case of an open circuit in the starting loopthose relays which are connected to the starting wires beyond the breakwill not be energized, and the last lamp lighted therefore will indicatethe approximate location of the trouble. In case the latter supervisionis not desired,

however, all but one of the relays may be it will be operated as yusualto locate thef ground group and unlock the group relayto restore groundto the group test contact; but when in the rotary movement. the .testwiper 121 arrives at -testycontact 163," it will lind lzeotential andtherotation will oo ntinu'e. .,bviously then, were no speclal means`adopted to prevent it, the switch would continue to buzz. f Suchcontingency is obviated by providing the rotary-shaft with an extratooth so that .ontheeleventh rotary step the wipers will be rotatedj odthefbank. The revision of such an extra tooth on-the shag is oldin thejart, switches of-manytypeshaving been used in the past which have morethan ten teethlto. the ro.

= 122 and 123 are not in engagement with a' Gil calling line, -or anyother line,l no holding circuit will be established," and the switchwill be releasedfollowing the deenergization of the slow-acting vrelay110..

Having described. my invention, what ll. consider to be newand desire`to have prof. tectedby. Letters Patent will be pointed out in theappendedclaims. L

What lt claim as my invention is:

1. ln a telephone system, a subscribers line, a trunk'line having twobranches, means for connecting said line and trunk. line, a selectorswitch for one branch, a calling device at the station on said line for-operating said switch to extend a connec, tion over the1 associatedbranch, a finder switch, and another 'calling device at the station onthe said line manually operable after the line and trunk are connected,and means responsive to said-second calling device for causing saidfinder to extend a connection overthe other of said branches. Y In. atelephone, system, 'a subscribers. line,a trunk line having twobranches, the first branch extending toward an operators switchboard,and thel second branch extend-V 'ing toward a called line, means forconnecting said subscribers line whencalling with `.said trunk line,switch hook springs at the Stationen thecalling. line for controllingsaid connecting 'mean-s, a. variable impulse .sender and a .circuitchanging switchl at the said station, and automaticswitching mechanismat the exchange .for extending thev calling line. over said first branchto said switchboard res onsiveto .the'actuation of saidgswitch, an .forextending said calling lineito a called line over said second branchpesano? responsive-to' the actuation of saidcalling device. jf, f.3...lln a telephone system, a subscribers line, a trunk lineterminatingin an auto-f matic selector switch, a finder switch, a branch ot saidtrunk line terminating in the .bank of said finder switch, means forextending lsaid line when calling tosaid trunk line, an impulse senderat the sub# 'station on said selector switch, and an -auxiliary deviceeration of said 'finder switch.

4. In a line, 'matic-switch, a finder switch, a branch- -of "said trunkline terminatinglin vthe bank'off said finder switch, means forextendingsaid" line when calling to said trunk line, an im-` pulsesender at the ing line forl operatingsaid selector switch, an auxiliarinitiating t e operation of said and means the connection is released.

the calling. line for operating ,7.,

substationon the calltelephone system, a subscribers a vtrunk lineterlnlnating 1n an auto.-

device associated .therewith'for' 4finder switch,". whereby ifeither theselector ..gswitch or the finder switch is operated the .5. In a.telephone system, a subscribers# line,. a Atrunk line having twobranches, an automatic switchfor extendlng one of said branchesto'anoperators pos1t1on, a, numerical automatic switch individual tosaid trunk line for extending the other of said branches toward anothersubscribe-rs line, means for,

connecting said-first linewhen calling'with' v said trunk line, andmeans for then imme- ^dia`tely operating .either of. said switchesseparately at the option of the calling subfscriber. A I 6. In. atelephone-l system, a subscribers line, la trunk line having twobranches, an automa-tic switch for .extending one of said branches to.anv operators position, a numerical automatic switch individual to saidtrunkline for extending the other of said branchestoward anothersubscribers line, means for connecting said first line when calling-withsaid trunk line, and separate controlling devices for respectively, atthe substation on the call-` ing line,- each controlling devicebeingmanswitch, switching mechanism for connecting the said subscribers linewhen calling with its the said switches,

ico

respectively, separate controlling l relays and operating magnets foreach said trunk linoe, a device at the statlon onlthe calling line forcontrolling said mechanism, and manually operableA controlling meanswheieb the subscriber on the calling line is ena led to operate eitherof said switches as soon as his line is connected to the said trunkline.

8.l In a telephone system, a subscribers 1 line, a trunk hne having twobranches extending to forward and backward selecting automatic switches,respectively, separate controlling relays and operating magnets in eachswitch, mechanism for yconnecting the said subscribers line when callingwith'said trunk line, switch hook springs at the station on said linefor controlling said mechanism, separate subscriber controlled devicesin the line circuit at said station, and circuit connections wherebyeach of said switches is rendered responsive only to a particular one ofsaid devices.

9. In a telephone system, a subscribers line,a trunk line having twobranches' each terminating in an automatic switch, means for connectingthe 'said line when calling with said trunk line, an impulse sender anda push button in the line circuit at the substation on the callingline,and circuit connections at the exchange whereby one of said switches isrendered responsive to sai-d impulse sender and the other of saidswitches to said push button.`

10. In a telephone system, a subscribers line, a trunk line having twobranches each terminating. in an automatic switch, means for connectingthe said line when calling with said trunk line, and separatecontrolling devices operated. independently for operating the respectiveswitches, said devices located at the substation on the calling line andcontrolling the two sides of the subscribers line in series to operatesaid switches.

11. In a telephone system,A lines divided into groups, an automaticswitch having group and line selecting movements and having no normalposition as regards the said groups, means for operating saidswitch toselect a desired one of said lines, with means for preventing a groupselecting movement thereof it' the said switch is already associ'atedwith the proper group. Y

12. In a telephone system, lines divided into groups, a switch havingautomatic group and line selecting movements and having no normalposition as regards the said groups, means for initiating the operationof s'aid switch to select a desired one of said lines, with meanspermitting the omission of the group selecting movement if the saidswitch is already associated with the proper group.

. 13. In a' telephone system, lines divided into groups, a plurality ofswitches having automatic group and line selecting movements, saidswitches being normally associated, respectively, with the groups lastserved, and means for initiating the operation of one of said switchesto select a desired line, the .switch operated being. one which isalready associated with the proper group.

14. In a telephone system, lines divided into groups, a plurality ofswitches having automatic group and line selecting movements, saidswitches being normally associated, respectively, with the groups lastserved, means for initiating the operation of-one of said switches toselect a desired line, the switch operated being one which is alreadyassociated with the proper group, and means whereby if the group inwhich the desired line is located has no switch asociated therewith thatswitch will be operated which requires the shortest group selectingmovement.

15. In a telephone system, a plurality of lines divided 'into groups, aplurality of finder switches associated indiferently with the variousgroups and having group and line selecting movements, and meansresponsive to a call received over one of said lines n for starting thatone of said switches which requires the shortest group selectingmovement to locate the calling line.

16. In a telephone system, a plurality of l lines divided into groups, aplurality of finder switches having group and line selecting movementsfor extending calls received over said lines, each switch when idlebeing associated withI the group last served, and means responsive to acall for starting. that one of said switches which requires the shortestgroup selecting movement to locate the calling line. l

'17. In a telephone system, a plurality of lines divided into groups, aplurality of finder switches associated indiiierently with the variousgroups and having primary and secondary selective movements forselecting groups and lines, respectively, and means responsive to a callreceived over one of said lines for operating one of said finders in[either one or both of its selective movements dary selective movementsfor selectinggroups and lines, respectively, said finders having nonormal position as regards the said groups, and means responsive to acall received over one of said lines for starting the finder switchassociated with the proper group to find the said line by a secondary Kselective movement only.

19. In a telephone system, a plurality of lines divided into groups, afinder switch having group and line selecting movements.

for extending one of said lines when calling,

and means `for releasing said switch thereafter only in so far as itsllne selecting selecting movement thereof.

2Q. Ina telephone system, a plurality of lines divided into groups, afinderswitch having group and line selecting movements and operableresponsive to a call received over one of said lines to extend the callto another line, means for thereafter releasing said switch in so far asits line selecting movement 'is concerned, and means for retaining saidswitch in operated position in so far as its group 'selecting movementis concerned.

21. In a telephone system, a lurality of lines divided into groups,trunk ines, finder switches having primary and secondary selectivemovements for "selecting .groups and lines, respectively,.to extendcalls to idle trunk lines, releasing means' in each finder switch, andmeans for retaining each switch after disconnection in association withthe last selected group. ,Y

22. ln a telephone system, groups of lines an automatic switch havingprimary and secondary motor magnets for operating the .same to connectwith a desired one of said lines, independently operable primary andsecondary release magnets for restoring sald switch, and means foroperating sald secondary release magnet only to restore said switch inreadiness for another call.

23. In a telephone system, groups of lines, an automatic switch havingprimary and secondary motor magnets for operating the same to connectwith a desired one of said lines, independently operable primary andsecondary release magnets for restoring said switch, and circuitconnections for energizing in order the said primary release ma net, thesaid vmotor magnets, and the said secondary release magnet.

24. In a telephone system, a subscriber"s line, a trunk line, meansincluding an automatic switch for connecting said lines, an operatingmagnet and a release magnet in said switch, and automatic means foractuating said magnets alternately during the establishment of theconnection.

25. In a telephone system," groups of lines, an automatic switch havinggroup andline selecting'movements for connecting with a desired one ofsaid lines, means for restoring said switch as regards its lineselecting movement independent of restoration as regards its groupselecting movement, and means for again operating said switch to 'selecta line without restoring it as regards its group selecting movement.

acceso? 26. ln a telephone system, finder switches each operativethrough a plurality of stages for extending a connection, circuitconnectime interval between the starting of succes- V sive finders, andmeans actuated by said finders at the completion of preliminary stagesof their operation for terminating said time intervals. A

27. In a. telephone system, grou s of lines, finder switches havinggroup and line selecting movements for connecting with said lines, meansresponsive to calls for starting said finders, and circuit connectionspreventing simultaneous roup selection by two or more finders, whi epermitting group selecition by one finder to occur contemporaneouslywith 4line selection by another finder. I

28. In -a telephone system, a plurality of lines, finder switches havingprimary and secondary movement for extending calls received over saidlines, means responsive to a call for starting an idle finder, 'andmeans actuated durin the primary movement of the started fin er' but notin the secondary movement thereof for preventing the start ing ofanother finder switch.

29. lin a telephone system, a plurality of lines, finder switches havinga plurality of selective movements for extendingcalls received over saidlines, a starting circuit for starting said finders successivelyresponsive to successive calls, means for rendering said circuitineilective each'time a finder switch is started, and means forrendering said circuit again eective while each finder is performing itsfinal selective operation.

30. In a telephone system, a subscribers line, a trunk line terminatingin an operators position, a plurality ofy automatic switchessuccessively operable to extend said line when calling to said trunkline, a signal operated at an intermediate stage in the connectingoperation to warn the operator of the approach of the call, and meansfor momentarily flashing the said signal when the connection iscomplete.

31. In a telephone system, groups of lines', finder switches forextending calls received` over said lines, and a starting circuitincluding a normally closed contact for each of said groups in each ofsaid switches.

32. lin a telephone system, groups of lines, finder switches forextending calls received over said lines, a starting circuit includin anormally closed contact for each of sai groups in each of said switches,and means in each of said switches for opening one of said contacts,whereby the said circuit may be divided into sections.

33. In a telephone system, grou s of lines finder switches for extendingcal received a normally closed contact for each of said groups in eachofsaid switches, means in each of said swi-tches for opening one of saidcontacts whereby the said circuit may be div vided into sections, acontrolling relay for cach of said finder switches, and means forconnecting each relay to one of said sections.

34. In a telephone system, groups of lmes, finder switches for extendingcalls received over said lines, a starting circuit including a normallyclosed contact for each of said groups in each of said switches, andmeans in each of said switches effective when the switch is idle foropening one of said contacts, whereby the said circuit may be ldividedinto as many sections as there are idle switches.

35. In a telephone system, groups of lines, finder switches forextending calls received over said lines, a starting circuit including anormally closed contact for each of said -groups in each of saidswitches, means in each of said switches effective when the switch isidle for opening one of said contacts, whereby the said circuit may bedivided into as many sections as there arel idle switches, and 'astarting relay in each idle finder switch connected to one of saidsections.

36. In a telephone system, groups of lines, finder switches forextending calls received over said lines, a starting circuit includingall of said switches in series, and a plurality of branches of saidcircuit equal in number to the number of said groups, said branchesbeing all connected to said circuit at the same switch.

37. In a telephone system, groups of lines, finder switches forextending calls received over said lines, a loop circuit passing througheach switch as many times as there are groups, and a starting wi-re foreach group of lines joined to said circuit.

38. In a telephone system, groups of lines, a finder switch forextending a call received over one of said lines, relays individual togroups and lines, respectively, a starting. relay for said finder, and astarting circuit including one of said group relays, one of said linerelays and the said starting relay.

39. In a telephone system, a finde-r switch, a starting circuitincluding a low resistance controlling relay in said switch, and a highresistance alarm relay connectedin parallel with said controlling relay.

40. In a telephone system, a finder switch, a starting circuit includinga low resistance controlling relay in said switch, means for closingsaid circuit, a plurality of normally closed contacts inthe circuitbetween the point of closure and the said relay, and an alarm relay inparallel with said lirst relay and connected to the circuit between thepoint of closure and the said contacts, said relay being of highresistance whereby when the circuit is closed it will be renderedinoperative by the sliunting effect of Said first relay.

4l. In a telephone system, a trunk line havin two branches, means forconnecting "a calling subscribers line with said trunk line at theundivided end thereof, means for completing a talking connection overone of said branches, and means for supplying talking current to thecalling line over both of said branches in parallel.

42. In a telephone system, a plurality of lines divided into groups, anautomatic ,i

switch having primary and secondary movements to select groups andlines, respectively, said switch' when idle being associatedwith'diferent groups at different times, means controlled by a callingsubscriber in setting up a connection for causing both pr1mary .andsecondary movement of said switch for selecting one of said lines, andvto rotate without first moving vertically to zonnect the said callingline with said trunk 44. In la telephone system, a calling subscribersline, a trunk line, an automatic switch having primary and secondaryselective movements, and a device at the station on the calling linemanually operable after the receiver is removed for causing said switchto connect the said line and trunk line by means of a secondaryselective movement only.

45. In a telephone system, an automatic switch for use in connecting a,calling and called line, a wiper shaft'for said swi-tch, a magnet coilwo-und on said shaft as a core and movable with the shaft, and a circuitchanging Iarmature adapted to be attracted when the said coil isenergized.

46. In a telephone system, a finder switch for use in extending acalling line to a trunk line, a starter wire extending to said switch, amagnet for extending said starterl wire to another finder switch, and awiper shaft for said .rst finder constituting a core for said magnet.

47. In a telephone system, a finder switch for use in extending acalling line to a trunk line, a tes-t wiper for said finder, a magnetfor rendering said test wiper inoperative with respect to its associatedtest contacts, and a wiper shaft for said finder constituting a core forsaid magnet.

48. In a selector switch having hunting movements in two differentco-ordinate di-l iii-a rections, means for starting the contact armsfrom a variable initial position in the first co-'o'rdinate directionupon a call being inltiated, means for setting the conta/charms 1nthqirst cofordinate direction forv the selec-` tion ofa Contact row, andmeans for Setting the contact arms in the. second co-ordinate directionfor the selectlon of a particular ticular contact, means for restoring`the contact arms, means for automatically stopping the return movementof the contact arms upon the latter reaching a position opposite incase?to the Contact row vjust left, and means for starting the Contact armsfrom said. position in the first ctn-ordinate direction upon a 50. In a,selector switch having'- hunting movements in two co-ordinatedirections,`

fixed line contactsarranged in rows,means Afor-,starting the contactarms from a vari- 'v able initial position in thel first co-ordinatedirection for the selection of a contact row, means for setting thecontact arms inthe second (zo-ordinate direction for therselection of laparticular contact, and means for marking a contact row as engaged assoon 'as the switch has found the contactrow to .which the calling lineis connected.

Signed by me at Chicago, Cook County,

State of illinois, this 29th day of December, l

RODNEY G. RCHARDSON.

